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parallel lines

two lines that are coplanar and do not intersect

skew lines

lines that do not intersect and are not coplanar

parallel planes

two planes that do not intersect

transversal

a line that intersects two or more coplanar lines at different points

corresponding angles

two angles that are formed by two lines and a transversal and occupy corresponding positions

alternate interior angles

2 angles that are formed by 2 lines and a transversal and that lie between the 2 lines on opposite sides of the transversal

alternate exterior angles

2 angles that are formed by 2 lines and a transversal and that lie outside the 2 lines on opposite sides of the transversal

consecutive interior angles

2 angles that are formed by 2 lines and a transversal and that lie between the 2 lines on the same side of the transversal

flow proof

a type of proof that uses arrows to show flow of a logical argument statements are connected by arrows to show how each statement comes before it. and each reason is written below the statement it justifies